The Truth About Aspect Ratio

Have you ever gone to print a photo and been confused or frustrated by the way it's cropped when you get it back? It might look like someone zoomed in and cut off someone's head, or a whole side of the photo might be missing. Or worse (in my opinion): there might be white bars on two sides of the photo, in order to keep the photo intact.

That's aspect ratio at work. The ratio of the photo you took might be in conflict with the size you're trying to print.

While I offer free advice for printing when family, maternity, or newborn clients order photos from me, I also know that sometimes you like to print your own photos (I recommend Richmond Camera) and then have to figure it out on your own. So, here’s a history lesson and some math to help you do that.

The history of the evolution of aspect ratio

Back in the film days of photography, you couldn't take a photo of just any size. We won't take you back all the way to the invention of photography and glass plates - let's just go back 20+ years to when I was in the School of the Arts at Virginia Commonwealth University, when there were three main sizes of camera film. There was large format film (4x5"); medium format film (which came out square, or very slightly rectangular, based on your camera’s settings), and the very rectangular 35 millimeter (35mm), which is what most everyone used.

The most common and mainstream was 35mm. You could buy it at the grocery store, pop it in your camera and then take it back to the grocery store to have it developed once you took all the photos (disposable cameras are also 35mm).

diagram from https://www.easybasicphotography.com/35mm-equivalent.html

Where we came up with 2:3 aspect ratio

35mm film literally measured 35 millimeters from sprocket hole to sprocket hole (hence the name) but the size of the photo on the film was 24mm tall x 36mm across. Here comes the math: divide 24mm and 36mm by their largest common denominator (12), and you end up with 2mm x 3mm, or a 2:3 ratio. That means that when you printed photos, if you wanted the whole photo without cutting anything off, you needed to choose a paper that is also on a 2:3 ratio, like a 4x6" print (multiplying both sides of the ratio by two: 2x2=4; 2x3=6). If you wanted something bigger than 4x6", you could multiply up and get your bigger sizes, each without cutting anything off: 8x12 (multiplying by 4); 16x24 (multiplying by 8); 20x30 (multiplying by 10); etc.

Choosing a phone camera aspect ratio

Now that we live in the digital age, aspect ratio is still important but it's slightly different. You can set your phone camera to your favorite aspect ratio and shoot in that ratio directly. Want all your photos to be square? Set your aspect ratio to 1:1 in your phone settings and then whatever you fit in the frame is your photo. Personally, I like the 16:9 aspect ratio for phone photos. Everyone knows they're phone photos and I like that they're a little wider on the sides and shorter from top to bottom when you hold the camera horizontally.

4×3 is a little closer to a camera’s aspect ratio, if that matters to you.

Even though we no longer shoot in 35mm film, we have mostly grown accustomed to the 2:3 aspect ratio for printing photos, and most digital cameras still shoot in that format. Let’s do an example. Here is a photo in its original 2:3 ratio:

And then here it is cropped in various formats. From left to right on top are 5×7 and 8×10. These are the most popular crops for prints, even though they cut off part of your image. You can easily find frames in those sizes.

Then from left to right on the bottom: 8.5×11 (like a sheet of paper); and 1×1 square crop. It’s harder to find frames in these sizes but not impossible.

You can see that even in the 1:1 crop (bottom right) that you get the majority of the information in the frame and the photo still looks good. Aspect ratio and crop matters less when your subject is smaller in the frame. I like to fill my frame with my subject sometimes, though, and that can make off-ratio crops problematic. Look what happens when I fill the frame and then have to crop it for an 8×10:

A solution for an 8×10 crop

Cropping for an 8×10 means I’m losing either the baby feet at the bottom of the image, or as the photo on the right demonstrates, cut the photo off at the baby’s head, which is a total dealbreaker. This is where cropping gets tricky. If I wanted this image around 8×10 size, I'd print it as an 8×12 size instead. 8×12 prints are slightly harder to frame because 8×12 frames are harder to find, but they're not impossible to find. (We also won't get into how I think this actually needs to be a 16×24 canvas hanging prominently in the hallway.)

Also, a side note about canvases and cropping - if you choose to wrap the image around the sides of the canvas, you're going to lose whole inches of your image to the wrap. I tend to choose black or white on the edges for that reason.

I hope this little intro to aspect ratio helps as you print your photos or choose sizes for prints in your gallery. In this case, size matters. And that's the truth.